Air bag apparatus

ABSTRACT

In an air bag apparatus structured such that an air bag ( 11 ) housed in a part of a vehicle in a folded manner is inflated and deployed by a gas supplied from an inflator ( 14 ) so as to protect an occupant, the gas supplied from the inflator ( 14 ) is dispersed in a three-dimensional direction by a shower head ( 13   a ) so as to be supplied to a gas passage ( 11   b ) of the air bag ( 11 ).

This is a Continuation of application Ser. No. 11/583,071 filed Oct. 19,2006, which in turn is a Continuation of U.S. application Ser. No.10/450,739 filed Jun. 17, 2003, now U.S. Pat. No. 7,147,244, which is aNational Phase of PCT Application No. PCT/IB01/02692 filed Dec. 27,2001. The entire disclosures of the prior applications are herebyincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to an air bag apparatus equipped in avehicle, that is, an air bag apparatus structured such that an air baghoused in a part of the vehicle in a folded manner inflates and deploysby a gas supplied from an inflator so as to protect an occupant.

BACKGROUND OF THE INVENTION

This kind of air bag apparatus includes, for example, a structure inwhich an air bag housed along a roof side rail is inflated and deployedin a curtain-like shape along a side wall of a vehicle compartment by agas supplied from an inflator so as to protect a head portion of anoccupant, and a structure in which an air bag housed in an instrumentpanel is inflated and deployed toward an inner portion of the vehiclecompartment due to the gas supplied from the inflator so as to protect ahead portion and a chest portion of the occupant.

The conventional air bag apparatus mentioned above includes a structurein which an inner tube is internally provided along a gas passage (aninflow portion) of an air bag so as to restrict bag damage by the gassupplied to the air bag from the inflator, for example, as disclosed inJapanese Patent Application Laid-Open No. 11-321536, and a structure inwhich a cylindrical body is provided along a gas passage of an air bagso as to restrict bag damage by a gas supplied to the air bag from aninflator, for example, as disclosed in Japanese Patent ApplicationLaid-Open No. 11-301394 and 2000-127886.

In these air bag apparatus, since the inner tube or the cylindrical body(a protecting member) mentioned above is provided in the gas passage ofthe air bag so as to restrict bag damage by the gas supplied to the airbag from the inflator, there is a risk that the inner tube or thecylindrical body mentioned above inhibits folding of the air bag, makingit more difficult to house the air bag in the vehicle and cause a costincrease of the air bag apparatus.

On the contrary, in the air bag apparatus, it is necessary to satisfyvarious requirements in view of inflating and deploying performance ofthe air bag (a requirement of making a period of time after startinginflation and deployment until completion equal to or shorter than a settime, a requirement of maintaining an initial internal pressure afterstarting inflation and deployment until completion equal to or greaterthan a high set pressure, a requirement of maintaining an internalpressure equal to or greater than a low set pressure for a predeterminedtime after an initial predetermined time has elapsed after completinginflation and deployment, and the like).

In order to reduce the period of time for completing inflation anddeployment of the air bag and increase the initial internal pressure,there is generally employed a countermeasure of increasing a gassupplying capacity of the inflator. However, when increasing the gassupplying capacity of the inflator, the bag damage is increased and itis impossible to increase a time of maintaining the internal pressure.Accordingly, it is necessary to sufficiently apply a coating for keepingairtightness, for example, onto a surface of the air bag so as torestrict bag damage and increase airtight performance, or it isnecessary to increase a gas supply capacity of the inflator in additionto increasing airtight performance of the air bag. In view of this,improving the inflating and deploying performance of the air bag andreducing a cost is contradictive. Such a problem can be resolved byrestricting the bag damage of the air bag by means capable of beingrealized at a low cost.

DISCLOSURE OF THE INVENTION

In accordance with a first aspect of the present invention, there isprovided an air bag apparatus structured such that an air bag housed ina part of a vehicle in a folded manner is inflated and deployed by a gassupplied from an inflator so as to protect an occupant, wherein the gassupplied from the inflator is dispersed in a three-dimensional directionso as to be supplied to a gas passage of the air bag.

In accordance with the first aspect mentioned above, the gas suppliedfrom the inflator is dispersed into the gas passage of the air bag inthe three-dimensional direction. Accordingly, at an early stage ofinflation and deployment of the air bag, the gas passage of the air baghoused in the folded manner is quickly expanded, whereby an area of theair bag under the gas pressure is increased and an effective passagearea in the gas passage can be sufficiently secured.

Accordingly, a part of the gas passage in the air bag is not put under alarge load due to the supplied gas, and it is possible to restrict bagdamage in the portion mentioned above. Therefore, it is possible tosimplify a countermeasure applied to the gas passage, that is acountermeasure against the gas pressure in the air bag, it is possibleto easily fold the air bag compact, it is possible to make it easier tohouse the air bag in the vehicle, and it is possible to reduce a cost ofthe air bag. Further, it is possible to improve a gas supplyingperformance in the gas passage by securing an effective passage area inthe gas passage, and it is possible to improve inflating and deployingperformance of the air bag.

In accordance with the first aspect, in the gas injection port exposedto the gas passage of the air bag, it is possible to disperse the gassupplied from the inflator in the three-dimensional direction. In thiscase, it is also possible to employ flow changing means for changing aflow of the gas supplied from the inflator or it is also possible toemploy flow dividing means for dividing the flow of the gas suppliedfrom the inflator into a plurality of sections. In accordance with thestructures mentioned above, it is possible to efficiently obtain anoperating effect due to the dispersion of the gas mentioned above in thethree-dimensional direction.

In accordance with a second aspect of the present invention, there isprovided an air bag apparatus structured such that an air bag housed ina part of a vehicle in a folded manner is inflated and deployed by a gassupplied from an inflator so as to protect an occupant, wherein a showerhead for dispersing the gas supplied from the inflator in athree-dimensional direction is disposed so as to face a gas passage ofthe air bag. In accordance with the aspect, it is also possible toachieve an operating effect by the dispersion in the three-dimensionaldirection of the gas mentioned above.

In the second aspect mentioned above, the structure can be made suchthat the shower head has a plurality of injection holes.

Further, in the second aspect mentioned above, the structure can be madesuch that the shower head is formed in a semispherical shape and has aplurality of injection holes on a spherical surface thereof. Inaccordance with this structure, it is possible to radially inject andsupply the gas so as to improve an efficiency of supplying the gas. Inaccordance with this structure, it is also possible to improve inflatingand deploying performance of the air bag.

In these cases, the structure can be made such that the injection holesof the shower head are provided in symmetric with respect to a point ofa center of the shower head. In accordance with this structure, evenwhen the shower head is assembled in a state of rotating around thecenter thereof, it is possible to obtain the gas injecting performancewith no change. Accordingly, in the case that the shower head isintegrally assembled in the inflator, a flexibility in mounting theinflator to the vehicle is increased.

Further, in these cases, the structure can be made such that the air bagis housed along a roof side rail and is inflated and deployed in acurtain-like shape along a vehicle compartment side wall due to the gassupplied from the inflator so as to protect a head portion of theoccupant, the air bag is provided with a front seat inflating portion, arear seat inflating portion and a gas passage for communicating upperportions of both of these inflating portions, and the shower head isdisposed so as to face the gas passage. In accordance with thisstructure, the gas supplied from the inflator is dispersed in thethree-dimensional direction by the shower head in the gas passage of theair bag provided with the front seat inflating portion and the rear seatinflating portion. Accordingly, in addition that it is possible toobtain the operating effect given by the dispersion of the gas in thethree-dimensional direction mentioned above, it is possible to properlydistribute and supply the gas toward the front seat inflating portionand the rear seat inflating portion, and it is possible to properlyinflate and deploy the front seat inflating portion and the rear seatinflating portion.

Further, in this case, it is possible to set opening areas of aninjection hole for the front seat and an injection hole for the rearseat provided in the shower head corresponding to capacities ofexpansion chambers in the front seat inflating portion and the rear seatinflating portion. In accordance with this structure, it is possible tosubstantially coincide an inflating and deploying timing of the frontseat inflating portion with that of the rear seat inflating portion inthe air bag, whereby it is possible to reduce a period of time afterstarting inflation and deployment of the air bag until completion, andit is possible to improve a motion during inflating and deploying theair bag.

Further, the shower head may be formed by a mesh. Further, the showerhead may be formed by a porous body. In accordance with thesestructures, it is also possible to achieve the operating effect given bythe dispersion in the three-dimensional direction of the gas. In thesecases, it is possible to easily change and set a dispersion performanceby changing an aspect or a material of the shower head.

In these cases, the shower head may be formed in a semispherical shape.In accordance with this structure, it is possible to inject and supplythe gas to a whole in the three-dimensional direction with a goodbalance.

Further, the shower head may be provided in a front end of a diffuserpipe assembled in the inflator. In accordance with this structure, thegas can be supplied to an optimum position of the gas passage in the airbag, by a shape of the diffuser pipe, whereby it is possible to commonlyuse the inflator.

In this case, the shower head may be integrally provided in theinflator. In accordance with this structure, it is possible to reduce alength of a gas flow passage from the inflator to the gas passage of theair bag, whereby it is possible to reduce an inflating and deployingperiod of the air bag.

In these cases, the structure can be made such that the air bag ishoused along a roof side rail and is inflated and deployed in acurtain-like shape along a vehicle compartment side wall due to the gassupplied from the inflator so as to protect a head portion of theoccupant, the air bag is provided with an inflating portion for a frontseat and an inflating portion for a rear seat and a gas passage forcommunicating upper portions of both of these inflating portions, andthe shower head is disposed so that the gas can flow into the gaspassage in a crossing manner. In accordance with this structure, the gassupplied from the inflator is dispersed in the three-dimensionaldirection by the shower head in the gas passage of the air bag providedwith the front seat inflating portion and the rear seat inflatingportion. Accordingly, in addition that it is possible to obtain theoperating effect given by the dispersion of the gas in thethree-dimensional direction mentioned above, it is possible to properlydistribute and supply the gas toward the front seat inflating portionand the rear seat inflating portion, and it is possible to properlyinflate and deploy the front seat inflating portion and the rear seatinflating portion.

Further, in the case mentioned above, the structure can be made suchthat the shower head does not protrude within the gas passage of the airbag. In accordance with this structure, it is possible to prevent a foldof the air bag from being blocked out by the shower head, and it ispossible to fold the air bag in a compact manner, thereby it is not mademore difficult to house the air bag to the vehicle.

Further, in the case mentioned above, the structure can be made suchthat the inflator is arranged in a center portion in a longitudinaldirection of a vehicle. In accordance with this structure, it ispossible to reduce a length of each of the gas flow passages from theinflator to the front seat inflating portion and the rear seat inflatingportion in the air bag, whereby it is possible to reduce the inflatingand deploying period of the front seat inflating portion and the rearseat inflating portion in the air bag.

In the case mentioned above, the structure can be made such that theinflator is arranged in a longitudinal direction along a roof side railabove the air bag, or the inflator is arranged in a vehicle widthdirection along a roof panel above the air bag. In these cases, aflexibility in mounting the inflator is high.

In the case mentioned above, the diffuser pipe may be formed in asubstantially J shape. In accordance with this structure, it is possibleto arrange the inflator in the longitudinal direction along the roofside rail or arrange the inflator in the vehicle width direction alongthe roof panel, with keeping the same structures of the air bag, theinflator and the diffuser pipe, whereby it is possible to reduce a costdue to use the parts commonly.

Further, the shower head provided in the front end of the diffuser pipeassembled in the inflator, or the shower head integrally provided in theinflator may be coaxially arranged with respect to the longitudinaldirection of the gas passage communicating with the inflating chamber ofthe air bag. In this case, it is also possible to obtain the operatingeffect given by the dispersion of the gas in the three-dimensionaldirection mentioned above.

In this case, the structure can be made such that the inflator isarranged in front of or at the rear of the vehicle of the air bag.Further, the shower head may be arranged in the gas passage at a portionof the air bag communicating with the inflating chamber. In accordancewith the structures mentioned above, it is possible to directly supply apart of the gas dispersed in the three-dimensional direction by theshower head to the inflating chamber of the air bag.

Further, the structure can be made such that a plurality of injectionholes provided in the shower head are concentrically arranged with acenter of the front end of the shower head so as to form a plurality oflines. In accordance with this structure, it is possible to suitably seta dispersion effect of the gas on the basis of an arrangement of theinjection holes, and it is possible to reduce bag damage and improve agas supplying efficiency with a good balance.

In the case mentioned above, the structure can be made such that aplurality of inner and outer injection holes concentrically arranged andbeing adjacent to each other in a radial direction are arranged in acircumferential direction so as to form a zigzag form. In accordancewith this structure, it is possible to prevent the gas injected from aplurality of inner and outer injection holes concentrically arranged andbeing adjacent in the radial direction from being interfered with eachother, it is possible to disperse the gas to the gas passage of the airbag from the respective injection holes of the shower head with a goodbalance, and it is possible to further reduce the bag damage and furtherimprove the gas supplying efficiency.

Further, the structure can be made such that the shower head is formedin a stepped shape having multiple steps which become smaller toward thefront end, and a plurality of injection holes are formed in therespective step portions in an inclined manner. In accordance with thisstructure, since the shower head is formed in the stepped shape havingmultiple steps which become smaller toward the front end of the showerhead, it is possible to secure a gas pressure within the front end ofthe shower head, it is possible to level the gas pressure at a time whenthe gas flows in the respective injection holes and it is possible tolevel the gas flow flowing through the respective injection holes.Further, since a plurality of injection holes are formed in therespective step portions in the inclined manner, it is possible to formthe substantially conical gas flow expanding downward in a concentricand multiple shape, and it is possible to diffuse the gas flow with agood balance.

Further, the structure can be made such that the injection holes areformed in a fan shape expanding toward the front end. In accordance withthis structure, a pressure loss due to a shearing resistance (a wallsurface resistance) becomes greater in comparison with the structure ofthe injection holes having a complete round shape, and an angle ofdiffusion of the gas flow is increased. Accordingly, by properly settingan opening angle of the fan shape, it is possible to adjust the gas flowand adjust a deploying property and a directivity of the air bag.

Further, the structure can be made such that the front end of the showerhead is formed in an asymmetrical shape with respect to a center axisthereof and the injection holes are formed in the asymmetrical surface.In accordance with this structure, by properly setting the front endshape of the shower head, it is possible to adjust the gas flow andadjust the deploying property and the directivity of the air bag.

Further, the structure can be made such that the injection hole isformed in a stepped shape and a thickness of a minimum hole portion ismade small. In accordance with this structure, it is possible to reducethe pressure loss in the injection hole while securing a strengthrequired for the shower head.

Further, the structure can be made such that the injection holes formedin the front end wall of the shower head are inclined with respect tothe wall surface of the front end wall. In accordance with thisstructure, an apparent opening area of the inclined injection holes isreduced and an amount of the pressure loss is increased. Further, it ispossible to adjust the gas flow by changing the distribution or theangle of inclination of the inclined injection holes, and it is possibleto adjust the deploying property and the directivity of the air bag.

Further, the structure can be made such that the shower head is formedin a closed-end cylindrical shape or a closed-end polygonal tubularshape, the injection holes are formed in the front end wall of theshower head, and the injection holes are formed so as to ride over thefront wall of the shower head and a peripheral wall. In accordance withthis structure, it is possible to disperse (diffuse) the gas in multipledirections on the basis of a simple shape (structure). Further, theinjection holes riding over the front end wall of the shower head andthe peripheral wall can be easily formed by cutting the front end of theshower head obliquely, whereby it is easy to manufacture the shower headand it is possible to reduce a cost of the shower head.

Further, the structure can be made such that the front end portion ofthe diffuser pipe is formed so as to have a small diameter and theshower head is fitted and fixed to an outer periphery of the front endportion of the diffuser pipe. In accordance with this structure, it ispossible to easily change the dispersion property of the gas, forexample, corresponding to a shape, a magnitude or the like of the airbag, by replacing the shower head. Further, since the shower head may bemanufactured independently, it is easy to process the injection holes inthe shower head, and it is possible to commonly use the diffuser pipe,and widely reduce a cost.

In the case mentioned above, the structure can be made such that a gassupply port forming portion of the air bag is fixed to the step portionformed by the front end portion of the diffuser pipe and the showerhead. In accordance with this structure, since it is possible toeffectively utilize the step portion formed by the diffuser pipe and theshower head so as to fix the diffuser pipe and the shower head to theair bag, it is possible to improve an assembling operability and improvea fixing strength.

Further, the structure can be made such that hole diameters are madedifferent between the front seat injection hole and the rear seatinjection hole which are provided in the shower head, whereby it ispossible to set the opening areas of the front seat injection hole andthe rear seat injection hole corresponding to the capacities of theinflating chambers in the front seat inflating portion and the rear seatinflating portion. In accordance with this structure, it is possible tosubstantially coincide an inflating and deploying timing of the frontseat inflating portion with that of the rear seat inflating portion inthe air bag, whereby it is possible to reduce a period of time afterstarting inflation and deployment of the air bag until completion at alow cost, and it is possible to improve a motion during inflating anddeploying the air bag without increasing a working process applied tothe injection holes of the shower head.

In the case mentioned above, the structure can be made such that thefront seat injection holes and the rear seat injection holes arerespectively constituted by a plurality of injection holes, and a holediameter of any one thereof is gradually reduced toward the center ofthe front end in the shower head. In accordance with this structure, itis possible to gradually reduce the gas flow injected corresponding tothe hole diameter of the injection holes, it is possible to permit thegas to have a directivity, and it is possible to adjust the motionduring inflating and deploying the air bag.

Further, the structure can be made such that numbers of holes are madedifferent between the front seat injection hole and the rear seatinjection hole which are provided in the shower head, whereby it ispossible to set the opening areas of the front seat injection hole andthe rear seat injection hole corresponding to the capacities of theinflating chambers in the front seat inflating portion and the rear seatinflating portion. In accordance with this structure, it is possible tosubstantially coincide an inflating and deploying timing of the frontseat inflating portion with that of the rear seat inflating portion inthe air bag by a working process applied to the injection holes of theshower head by means of the same tool (a working process of increasingthe number of the injection holes in a side where an opening area isincreased), whereby it is possible to reduce a period of time afterstarting inflation and deployment of the air bag until completion whilereducing the bag damage due to an increase of the number of theinjection holes (a reduction of the gas flow speed), and it is possibleto improve the motion during inflating and deploying the air bag.

Further, the structure can be made such that an auxiliary inflatingchamber communicating with the gas passage at an upper end below thefront end of the shower head so as to extend in a vertical direction isprovided in the air bag. In accordance with this structure, the gas alsoflows to the auxiliary inflating chamber of the air bag during inflatingand deploying the air bag, whereby the deployment downward of the airbag is promoted. Accordingly, it is possible to reduce the time untilcompleting the deployment of the air bag.

In the case mentioned above, the structure can be made such that a lowerend of the auxiliary inflating chamber is communicated with at least oneof the front seat inflating portion and the rear seat inflating portion.In accordance with this structure, it is possible to supply the gas toat least one of the front seat inflating portion and the rear seatinflating portion through the auxiliary inflating chamber, and it ispossible to further reduce the time until completing the deployment ofthe air bag.

Further, in the case mentioned above, the structure can be made suchthat an opening area of a passage for communicating the auxiliaryinflating chamber with the front seat inflating portion and an openingarea of a passage for communicating the auxiliary inflating chamber withthe rear seat inflating portion are set corresponding to the capacitiesof the inflating chambers in the front seat inflating portion and therear seat inflating portion. In accordance with this structure, it ispossible to substantially coincide the inflating and deploying timing ofthe front seat inflating portion with that of the rear seat inflatingportion in the air bag while reducing the period of time untilcompleting the deployment of the air bag.

Further, the structure can be made such that distribution in alongitudinal direction with respect to the center of the front end inthe shower head is made different between the front seat injection holeand the rear seat injection hole which are provided in the shower head.In accordance with this structure, it is possible to adjust an injectionpressure of the gas passing through the front seat injection hole andthe rear seat injection hole, and it is possible to adjust the inflatingand deploying timing of the front seat inflating portion and the rearseat inflating portion in the air bag.

Further, the structure can be made such that the injection hole providedin the shower head is formed in a long hole longer in the longitudinaldirection. Further, the structure can be made such that an opening areaof the injection hole being most apart in the longitudinal directionfrom the center of the front end of the shower head among a plurality ofinjection holes provided in the shower head is made larger than anopening area of the other injection holes. In accordance with thesestructures, it is possible to increase the gas flow in the longitudinaldirection, it is possible to positively inflate and deploy the air bagby a leveled gas flow, and it is possible to inflate and deploy the airbag with keeping the directivity in the longitudinal direction.

Further, the structure can be made such that opening areas of theinjection holes provided in the shower head are made different betweenan inner portion and an outer portion in the vehicle width direction.Further, the structure can be made such that numbers of the injectionholes provided in the shower head are made different between an innerportion and an outer portion in the vehicle width direction. Inaccordance with these structures, it is possible to inflate and deploythe air bag in the portion in which the shower head is arranged, towardthe inner portion or the outer portion in the vehicle width direction.Accordingly, for example, in the case of setting so as to inflate anddeploy the air bag toward the inner portion in the vehicle widthdirection, it is possible to prevent the air bag in the middle ofinflating and deploying from being caught on by an upper end portion ofa B pillar garnish or the like, or in the case of setting so as toinflate and deploy the air bag toward the outer portion in the vehiclewidth direction, it is possible to inflate and deploy the air bag alongthe side glass surface.

Further, the structure can be made such that the gas supply port of theair bag to which the shower head is inserted is formed in a shapeexpanding at a predetermined angle toward the gas passage, and an angleof diffusion of the gas supplied from the shower head is made equal toor less than the predetermined angle. In accordance with this structure,it is possible to achieve both of a damage reduction of the gas supplyport in the air bag and an improvement of diffusing property of the gas.

Further, the structure can be made such that an auxiliary inflatingchamber communicating with the gas passage at an upper end below thefront end of the shower head and extending in a vertical direction isprovided in the air bag, and an angle of diffusion in the longitudinaldirection of the gas supplied from the shower head is set to be equal toor greater than a predetermined value so that the gas is injectedfarther forward than an R end point disposed in a forward portion of theupper end of the auxiliary inflating chamber and farther rearward thanan R end point disposed in a rearward portion of the upper end. Inaccordance with this structure, it is possible to well distribute thegas to the forward portion and the rearward portion of the gas passagewhile securing the inflow of the gas to the auxiliary inflating chamber,and it is possible to improve the gas distributing property toward theforward portion, the rearward portion and the downward portion from theshower head.

In the case mentioned above, the structure can be made such that theangle of forward diffusion of the gas from the shower head is madedifferent from the angle of rearward diffusion. In accordance with thisstructure, it is possible to change the gas distribution to the forwardportion and the rearward portion in the gas passage corresponding to theshape of the air bag (for example, a ratio of capacity of the inflatingchamber between the front seat inflating portion and the rear seatinflating portion, and a shape of the inflating chamber), and it ispossible to inflate and deploy the air bag in an optimum state.

Further, the structure can be made such that diffusing means fordiffusing the gas supplied from the inflator in the three-dimensionaldirection is provided in a side of the air bag. In this case, it is alsopossible to achieve the operating effect given by the dispersion of thegas in the three-dimensional direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view showing an embodiment obtained byapplying the present invention to a head portion protecting air bagapparatus;

FIG. 2 is an enlarged side elevational view of an air bag module shownin FIG. 1;

FIGS. 3A to 3C are side elevational views of three kinds of air bagsincluding an air bag shown in FIG. 2;

FIGS. 4A to 4C are side elevational views of three kinds of tensionclothes including a tension cloth shown in FIG. 2;

FIG. 5 is a side elevational view of a diffuser pipe and an inflatorshown in FIG. 2;

FIG. 6 is an enlarged perspective view of the diffuser pipe and a showerhead shown in FIGS. 2 and 5;

FIG. 7 is an enlarged vertical cross sectional view of the shower headshown in FIG. 6;

FIG. 8 is a bottom elevational view of the shower head shown in FIG. 7;

FIG. 9 is an enlarged vertical cross sectional back view obtained byvertically cross sectioning the air bag shown in FIGS. 1 and 2 at a rearportion rather than the inflator in a state of folding and accommodatingstate;

FIG. 10 is an enlarged vertical cross sectional back view obtained byvertically cross sectioning the air bag shown in FIGS. 1 and 2 at a Bpillar portion in a state of folding and accommodating state;

FIG. 11 is a bottom elevational view showing a modified embodiment ofthe shower head shown in FIG. 8;

FIG. 12 is a bottom elevational view showing another modified embodimentof the shower head shown in FIG. 8;

FIG. 13 is a vertical cross sectional view showing a modified embodimentof the shower head shown in FIG. 7;

FIG. 14 is a vertical cross sectional view of an embodiment in which theshower head is formed by a mesh;

FIG. 15 is a bottom elevational view of the shower head shown in FIG.14;

FIG. 16 is a vertical cross sectional view showing a modified embodimentof the shower head shown in FIG. 14;

FIG. 17 is a vertical cross sectional view of an embodiment in which theshower head is formed by a porous body;

FIG. 18 is a vertical cross sectional view showing a modified embodimentof the shower head shown in FIG. 17;

FIG. 19 is a side elevational view of an embodiment in which the showerhead is integrally provided in an inflator;

FIG. 20 is a side elevational view of an essential portion showing anembodiment in which the present invention is applied to an air baghaving a gas supply port in a rear end portion;

FIG. 21 is a partly side elevational view showing a modified embodimentof the embodiment in which the shower head is integrally provided in theinflator;

FIG. 22 is an enlarged vertical cross sectional back view correspondingto FIG. 9 showing a modified embodiment of the diffuser pipe;

FIG. 23 is an enlarged vertical cross sectional back view obtained byvertically cross sectioning at the B pillar portion in a modifiedembodiment in which a front end of the diffuser pipe is arranged so asto overlap with the B pillar portion;

FIG. 24 is a bottom elevational view of an embodiment in which aplurality of injection holes are concentrically arranged in the showerhead so as to form a plurality of lines;

FIG. 25 is a bottom elevational view of an embodiment in which aplurality of injection holes are concentrically arranged in the showerhead so as to form a plurality of lines and inner and outer injectionholes adjacent to each other in a radial direction are arranged so as toform a zigzag shape in a circumferential direction;

FIG. 26 is a vertical cross sectional side view of an embodiment inwhich the shower head is formed in a stepped shape having multiple stepshaving smaller diameter toward a front end, and a plurality of injectionholes are obliquely formed in the respective step portions;

FIG. 27 is a bottom elevational view of the embodiment shown in FIG. 26;

FIG. 28 is a vertical cross sectional side view of an embodiment inwhich the shower head is formed in a stepped shape having multiple stepshaving smaller diameter toward the front end, and a plurality ofinjection holes are formed in the respective step portions in a fanshape expanding toward the front end;

FIG. 29 is a bottom elevational view of the embodiment shown in FIG. 28;

FIG. 30 is a vertical cross sectional side view of an embodiment inwhich the front end of the shower head is formed in an asymmetricalshape with respect to a center axis thereof, and the injection holes areformed on the asymmetrical surface;

FIG. 31 is a vertical cross sectional side view of an embodiment inwhich the injection hole is formed in the stepped shape and a thicknessof a minimum hole portion is reduced;

FIG. 32 is a vertical cross sectional side view of an embodiment inwhich the injection hole formed in the front end wall of the shower headis inclined with respect to the wall surface of the front end wall;

FIG. 33 is a perspective view of an embodiment in which the shower headis formed in a closed-end polygonal tube shape, the injection holes areformed in the front end wall of the shower head, and the injection holesare formed so as to ride over the front end portion and a peripheralwall of the shower head;

FIG. 34 is a perspective view of an embodiment in which a diameter ofthe front end portion of the diffuser is made smaller, and the showerhead is fitted and fixed to an outer periphery of the front end portionin the diffuser pipe;

FIG. 35 is a vertical cross sectional side view of an embodiment inwhich a gas supply port forming portion of the air bag is fixed to astep portion formed by the front end portion of the diffuser pipe shownin FIG. 34 and a step portion formed by the shower head;

FIG. 36 is a bottom elevational view of an embodiment in which holediameters are made different between an injection hole for a front seatand an injection hole for a rear seat which are provided in the showerhead;

FIG. 37 is a bottom elevational view of an embodiment in which the frontseat injection hole and the rear seat injection hole which are providedin the shower head are respectively constituted by a plurality ofinjection holes, and a hole diameter of the front seat injection holesis gradually reduced toward the center of the front end in the showerhead;

FIG. 38 is a bottom elevational view of an embodiment in which thenumber of the front seat injection holes provided in the shower head ismade more than the number of the rear seat injection holes;

FIG. 39 is a side elevational view of an embodiment in which anauxiliary inflating chamber communicating with the gas passage of theair bag at an upper end below the front end of the shower head andextending in a vertical direction is provided in the air bag;

FIG. 40 is a side elevational view of an embodiment in which a lower endof the auxiliary inflating chamber provided in the air bag iscommunicated with the rear seat inflating portion;

FIG. 41 is a side elevational view of an embodiment in which the lowerend of the auxiliary inflating chamber provided in the air bag iscommunicated with the front seat inflating portion and the rear seatinflating portion;

FIG. 42 is a bottom elevational view of an embodiment in which adistribution in the longitudinal direction with respect to the center ofthe front end of the shower head is different between the front seatinjection holes and the rear seat injection holes provided in the showerhead;

FIG. 43 is a bottom elevational view of an embodiment in which theinjection hole provided in the shower head is constituted by a long holelonger in the longitudinal direction;

FIG. 44 is a bottom elevational view of an embodiment in which anopening area of the injection hole most apart in the longitudinaldirection from the center of the front end in the shower head is madelarger than that of the other injection holes among the injection holesprovided in the shower head;

FIG. 45 is a bottom elevational view of an embodiment in which openingareas of the injection hole provided in the shower head are madedifferent between the inner portion and the outer portion in the vehiclewidth direction;

FIG. 46 is a bottom elevational view of an embodiment in which thenumbers of the injection holes provided in the shower head are madedifferent between the inner portion and the outer portion in the vehiclewidth direction;

FIG. 47 is a side elevational view of an embodiment in which the gassupply port of the air bag to which the shower head is inserted isformed in a shape expanding at a predetermined angle toward the gaspassage, and an angle of diffusion of the gas supplied from the showerhead is made equal to or less than a predetermined angle;

FIG. 48 is a side elevational view of an embodiment in which anauxiliary inflating chamber is provided in the air bag, an angle ofdiffusion in the longitudinal direction of the gas supplied from theshower head is made equal to or greater than a predetermined value, andthe gas is injected to a forward portion rather than an R end pointdisposed in a forward portion of an upper end in the auxiliary inflatingchamber and to a rearward portion rather than an R end point disposed ina rearward portion of the upper end; and

FIG. 49 is a side elevational view of an embodiment in which gasdispersing means is provided in a side of the air bag.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be given below of an embodiment in accordance withthe present invention with reference to the accompanying drawings. FIGS.1 to 10 show an embodiment in which the present invention is applied toa head portion protecting air bag apparatus for a passenger car vehicle.The air bag apparatus in accordance with this embodiment is providedwith an air bag module 10 constituted by an air bag 11 inflating anddeploying in a curtain-like shape along a side wall of a vehiclecompartment, a tension cloth 12 assembled in a front end portion of theair bag 11 and an inflator 14 assembled in an air tight manner in a gassupply port 11 a of the air bag 11 together with a diffuser pipe 13.

The air bag 11 is formed in accordance with a double elastic webbing sothat a direction of texture becomes longitudinally and vertically, has acoating for keeping airtightness applied to a surface thereof, has a gassupply port 11 a, a gas passage 11 b extending in a longitudinaldirection so as to substantially cross to a lower end thereofvertically, an inflating portion for a front seat 11 c and an inflatingportion for a rear seat 11 d communicating with each other through thegas passage 11 b, and has an intermediate non-inflating portion 11 e, afront end non-inflating portion 11 f and four mounting piece portions 11g. In this case, a mounting hole 11 g 1 to a roof side rail 21 isprovided in each of the mounting piece portions 11 g.

The front seat inflating portion 11 c is structured, as shown in FIGS. 1and 2, such as to protect a head portion Hf of an occupant Mf sitting ona front seat Sf (a seat arranged corresponding to a B pillar 23), and issectioned into four inflating chambers (cells) 11 c 4, 11 c 5, 11 c 6and 11 c 7 in an inner portion of a center thereof by three T-shapedsectioning portions (non-inflating portions) 11 c 1, 11 c 2 and 11 c 3provided in the center in a vertical direction, and the respectiveinflating chambers 11 c 4 to 11 c 7 are communicated with each other atboth upper and lower ends.

The rear seat inflating portion 11 d is structured, as shown in FIGS. 1and 2, such as to protect a head portion Hr of an occupant Mr sitting ona rear seat Sr, and is sectioned into three inflating chambers (cells)11 d 3, 11 d 4 and 11 d 5 in an inner portion of a center thereof by twoT-shaped sectioning portions (non-inflating portions) 11 d 1 and 11 d 2provided in the center in a vertical direction, and the respectiveinflating chambers 11 d 3 to 11 d 5 are communicated with each other atboth upper and lower ends.

The tension cloth 12 is formed in a triangle shape (a shape can besuitably changed) by a non-coat woven fabric which is thinner and moreinexpensive than the cloth constructing the air bag 11, is sewn up in afront end non-inflating portion 11 f of the air bag 11 at a rear endportion 12 a, and is structured such as to be assembled in an A pillar22 by a mounting hole 12 b 1 provided in the front end portion 12 b(refer to FIG. 1).

The diffuser pipe 13 is, as shown in FIGS. 2, 5 and 9, formed in a thinand substantially J shape, is assembled in an air tight manner in thegas supply port 11 a of the air bag 11 by using a fastening band 15 in astate of being integrally connected and fixed in an air tight manner toa male screw portion 14 b provided in a gas injection port 14 a of theinflator 14 by using a flare nut 13 b, has a diameter smaller than thatof the gas supply port 11 a and is set so that a desired gap is formedbetween the gas supply port 11 a and the diffuser pipe 13. This gapcorresponds to a gap allowing a gas radial injection at a front end ofthe diffuser pipe 13.

Further, the diffuser pipe 13 is arranged, as shown in FIG. 1, so that afront end thereof is directed obliquely downward along a door glass (aside glass) surface 41 (so as to be arranged to be substantiallyparallel to the door glass surface 41) as shown in FIG. 9, at a positiona little to the rear of the B pillar 23, and is structured such as tosupply the gas so as to cross to the gas passage 11 b extending in alongitudinal direction of the air bag 11 from the above.

Further, a shower head 13 a for dispersing (diffusing) the gas suppliedfrom the inflator 14 in a three-dimensional direction (a radialdirection) is integrally provided in a front end of the diffuser pipe 13(a gas injection port of the diffuser pipe 13), that is, a portionfacing to the gas passage 11 b of the air bag 11, and a length of afront end portion in the diffuser pipe 13 is set so that the shower head13 a does not protrude out within the gas passage 11 b of the air bag11.

The shower head 13 a has, as shown in FIGS. 6 to 8 in a detailed manner,a function of dispersing the gas supplied to the air bag 11 from theinflator 14 through the diffuser pipe 13 in a three-dimensionaldirection, and is formed in a substantially semispherical shape (referto FIG. 7) by a metal raw material, and a plurality of injection holes13 a 1 radially extending from a center O1 of a spherical surfacethereof are provided on the spherical surface in symmetrical withrespect to a point of a center (axis) of the shower head 13 a.

A plurality of injection holes 13 a 1 are constituted by an injectionhole provided in a center of the front end and eight injection holesprovided at a uniform interval in a circumferential direction above theinjection hole, and eight injection holes and the injection hole in thecenter of the front end have the same diameter. In this case, eightinjection holes provided at the uniform interval in the circumferentialdirection may be achieved so as to have a diameter larger (or smaller)than the injection hole in the center of the front end (the centerinjection hole may be omitted). Further, the shower head 13 a alsoserves as flow changing means for changing a flow of the gas suppliedfrom the inflator 14, and further serves as flow dividing means fordividing the flow of the gas supplied from the inflator 14 into aplurality of sections.

The inflator 14 is structured such as to inject and supply the gastoward the air bag 11 at a time of a side collision of a vehicle or at atime of a roll over of the vehicle, and is assembled in a roof side rail21 by a bracket 14 c with using a bolt 16 or the like, as shown in FIG.9. Further, the inflator 14 is arranged in a longitudinal directionalong the roof side rail 21 above the air bag 11 in a center portion inthe longitudinal direction of the vehicle, and is structured such as tobe covered by a roof head lining 31. In this case, the bracket 14 cshown in FIG. 9 corresponds to a bracket (an EA bracket) formed by a rawmaterial (an energy absorbing raw material) which can be easilyplastically deformed against an external force, and can absorb an energyat a stroke S until being brought into contact with the roof side rail21. In the case that an amount of energy is a lot, it is possible toattach an energy absorbing pad 39 onto a back surface of the roof headlining 31, as shown by a virtual line.

In the air bag apparatus in accordance with the embodiment structured inthe manner mentioned above, at a normal time, the air bag 11 and thetension cloth 12 are housed along the A pillar 22 and the roof side rail21 in a state that they are fold up in multiple layers in the verticaldirection and are housed in a breakable bag 17 (refer to FIGS. 9 and 10)in a compact manner, and are covered by an A pillar garnish (not shown)and the roof head lining 31.

FIG. 10 shows a cross section in a B pillar garnish 33 portion. Aprojection 38 a for preventing the inflating and deploying air bag 11from entering a back portion of the B pillar garnish 33 is formed on aback surface of an upper portion in the B pillar garnish 33. In thiscase, the projection 38 a may be achieved by a shape shown by a virtualline in FIG. 10 (a shape having an inclined surface in an upward bentportion), and in this case, inflation and deployment of the air bag 11is guided by the inclined surface so as to prevent the air bag 11 frombeing caught on an upper end of the B pillar garnish 33.

Further, at a time of the side collision, the roll over or the like ofthe vehicle, if the gas is injected out from the inflator 14 and the gasis supplied to the gas passage 11 b of the air bag 11 from the showerhead 13 a through the diffuser pipe 13, the air bag 11 deforms thecorresponding portion of the roof head lining 31 toward the innerportion of the vehicle compartment so as to deploy downward, and thetension cloth 12 deforms the corresponding portion of the A pillargarnish toward the inner portion of the vehicle compartment so as todeploy downward, whereby the air bag 11 inflates and deploys in thecurtain-like shape along the side wall within the vehicle compartment asshown in FIG. 1. At this time, the respective inflating portions 11 cand 11 d of the air bag 11 inflate and deploy toward a head portionprotecting area positioned in side portions of the head portions Hf andHr of the respective passengers Mf and Mr.

In this case, in this embodiment, one corresponding to the vehicle isselected as the air bag 11 constituting the air bag module 10 amongthree kinds of air bag 11A, 11B and 11C shown in FIGS. 3A to 3C, onecorresponding to the vehicle is selected as the tension cloth 12 amongthree tension cloths 12A, 12B and 12C shown in FIGS. 4A to 4C, and theair bag 11 and the tension cloth 12 are combined with a single kind ofdiffuser pipe 13 (provided with the shower head 13 a at the front end)shown in FIG. 5 and the inflator 14, whereby the air bag module 10 isconstructed.

Three kinds of air bags 11A, 11B and 11C shown in FIGS. 3A to 3C aresorted on the basis of a distance between the front and rear seats inall the kinds of passenger cars (accurately, as shown in FIG. 1, adistance Lo between hip points of the occupants Mf and Mr sitting on thefront and rear seats Sf and Sr existing at reference positions of frontand rear slides, and often called as a couple distance), and have afront seat inflating portion 11 c (which may be either common ordifferent among the respective air bags 11A, 11B and 11C) covering allthe protecting range in the respective front seat of a plurality ofkinds of cars included in the respective kinds (three kinds), and therear seat inflating portion 11 d (which may be either common ordifferent among the respective air bags 11A, 11B and 11C) covering allthe protecting range in the respective rear seat. In this case, in FIG.1, there is also shown a longitudinal sliding amount Lf of the frontseat Sf.

The protecting range mentioned above corresponds to a range of a headportion protecting area of the occupants sitting on the respective seatsat least including a petite woman (AF05) in U.S. women and a large man(AM95) in U.S. men, as shown in FIG. 2. In this case, in the front seatSf, there are respectively shown a regular sitting position at afrontmost of the petite woman (AF05) and a regular sitting position at arearmost of the large man (AM95). Further, shapes and dimensions ofthree kinds of tension cloths 12A, 12B and 12C shown in FIGS. 4A to 4Care set on the basis of longitudinal lengths between the respective airbags 11A, 11B and 11C and the respective A pillars 22 of a plurality ofkinds of cars employing the air bags.

Accordingly, it is possible to set the constituting parts of the air bagmodule 10 applied to all kinds of passenger cars (there are about twentyto thirty kinds of cars in one car maker producing multiple kinds ofpassenger cars) to three kinds of air bags 11A, 11B and 11C, three kindsof tension cloths 12A, 12B and 12C, a single kind of diffuser pipe 18and a single kind of inflator 14, whereby it is possible to reduce thenumber of the parts to be manufactured for the air bag module 10 appliedto all the kinds of the passenger cars (the number of supplied parts)and it is possible to reduce a cost due to a reduction of the parts.

Further, in the air bag apparatus in accordance with this embodiment,the gas supply port 11 a of the air bag 11 is provided between the frontseat inflating portion 11 c and the rear seat inflating portion 11 d,whereby it is possible to supply the gas to the front seat inflatingportion 11 c and the rear seat inflating portion 11 d in the air bag 11substantially at the same timing and it is possible to inflate anddeploy the front seat inflating portion 11 c and the rear seat inflatingportion 11 d in the air bag 11 substantially at the same timing for ashort time. Further, in the air bag apparatus in accordance with thisembodiment, since the sizes in the vertical direction of the respectiveair bags 11A, 11B and 11C are the same, it is possible to make the sizesin the vertical direction of all the air bag raw materials the same andit is possible to reduce the cost of the air bag itself.

Further, in accordance with this embodiment, the gas supplied from theinflator 14 is dispersed into the gas passage 11 b of the air bag 11 inthe three-dimensional direction (a radial direction of the shower head13 a, a dispersing direction in a gas flow direction) by the shower head13 a provided in the diffuser pipe 13. Accordingly, at an early time ofinflation and deployment of the air bag 11, the gas passage 11 b of theair bag 11 housed in the folded manner quickly expands in the verticaldirection, whereby an area of the air bag 11 exposed to the gas pressureis increased and an effective passage area in the gas passage 11 b canbe sufficiently secured.

Accordingly, a part of the gas passage 11 b in the air bag 11 is not putunder a large load due to the supplied gas, and it is possible torestrict bag damage in the corresponding portion. Accordingly, it is notnecessary to provide the protecting member against the gas pressure inthe gas passage 11 b of the air bag 11 (or it is possible to reduce thenumber of the protecting members), whereby it is possible to simplifythe air bag 11, it is possible to easily fold up the air bag 11 compact,it is possible to make it easier to house the air bag 11 to the vehicle,and it is possible to reduce the cost of the air bag 11. Further, bysecuring an effective passage area in the gas passage 11 b, it ispossible to improve the gas supplying performance in the gas passage 11b, it is possible to improve the inflating and deploying performance ofthe air bag 11, and it is possible to reduce the inflating and deployingperiod of the air bag 11.

Further, in this embodiment, since the shower head 13 a is formed in thesemispherical shape and has a plurality of radically extending injectionholes 13 a 1 on the spherical surface thereof, it is possible toradically inject and supply the gas so as to increase an efficiency ofdispersion and supply of the gas, whereby it is also possible toincrease the bag damage restricting effect of the air bag 11 and it ispossible to improve the inflating and deploying performance of the airbag 11. Further, since the injection holes 13 a 1 of the shower head 13a are provided in symmetrical with respect to a point of the center (theaxis) of the shower head 13 a, the gas injecting performance can beobtained without changing even when the shower head 13 a is assembled ina state of being rotated around the center thereof. Accordingly, it ispossible to change the assembling direction of the shower head 13 a, thediffuser pipe 13 and the inflator 14 in the vehicle with hardly changingthe gas injecting performance, so that a mounting flexibility of theinflator 14 to the vehicle is increased.

Further, in accordance with this embodiment, since the shower head 13 ais arranged so as to face the gas passage 11 b of the air bag 11, thegas supplied from the inflator 14 is dispersed in the three-dimensionaldirection by the shower head 13 a in the gas passage 11 b of the air bag11. Accordingly, it is possible to distribute and supply the gas towardthe front seat inflating portion 11 c of the rear seat inflating portion11 d of the air bag 11 accurately, and it is possible to inflate anddeploy the front seat inflating portion 11 c and the rear seat inflatingportion 11 d for a short time.

Further, in this embodiment, since the structure is made such that theshower head 13 a does not protrude out within the gas passage 11 b ofthe air bag, the fold-up of the air bag 11 is not disturbed by theshower head 13 a, it is possible to fold up the air bag 11 in a compactmanner, and it is not possible to make it more difficult to house theair bag 11 in the vehicle. Further, since the inflator 14 is arranged inthe center portion in the longitudinal direction of the vehicle, it ispossible to reduce the length of each of the gas flow passages from theinflator 14 to the front seat inflating portion 11 c and the rear seatinflating portion 11 d in the air bag 11, and it is possible to reducethe inflating and deploying period of the front seat inflating portion11 c and the rear seat inflating portion 11 d in the air bag 11.

Further, in accordance with this embodiment, since the diffuser pipe 13is formed substantially in the J shape, it possible to arrange theinflator 14 along the roof side rail 21 in the longitudinal direction orit is possible to arrange the inflator 14 along the roof panel 25 shownin FIG. 9 in the vehicle width direction, while keeping the air bag 11,the inflator 14 and the diffuser pipe 13 in the same structures, so thatit is possible to reduce the cost due to the common use of the parts.

Further, in accordance with this embodiment, since the shower head 13 ais provided at the front end of the diffuser pipe 13 assembled in theinflator 14, it is possible to correspond in the shape of the diffuserpipe 13 at a time of supplying the gas to the optimum position of thegas passage 11 b in the air bag 11, whereby it is possible to commonlyuse the inflator 14.

In the embodiment mentioned above, the bag formed in accordance with thedouble elastic webbing is employed as the air bag 11, however, thestructure can be realized by employing a sewn bag or a bonded (thermallywelded) bag. Further, in the embodiment mentioned above, the structureis realized by making all of eight injection holes 13 a 1 provided atthe uniform interval in the circumferential direction of the shower head13 a have the same diameter, however, as shown in FIGS. 11 and 12, inthe case that the front seat injection holes (three injection holes 13 a1 in the left side in the drawing) are made larger than the rear seatinjection holes (three injection holes 13 a 1 in the right side in thedrawing), and the opening areas thereof are set corresponding to therespective capacities of the front seat inflating portion 11 c and therear seat inflating portion 11 d (a total capacity of a plurality ofinflating chambers), it is possible to substantially coincide theinflating and deploying timing of the front seat inflating portion 11 cwith that of the rear seat inflating portion 11 d in the air bag 11,whereby it is possible to reduce the period of time from starting ofinflation and deployment of the air bag 11 to completing, and it ispossible to improve the motion during inflating and deploying the airbag 11.

Further, in the embodiment mentioned above, the shower head 13 a isrealized by forming in the semispherical shape, however, as shown inFIG. 13, the structure can be realized by forming the shower head 13 ain a shape in which a bevel (a taper portion) 13 a 2 is provided at afront end, and providing a radial injection hole 13 a 1 therein. In thiscase, a diameter of the injection hole 13 a 1 in the center of the frontend is made the same diameter as a diameter of the other injection holes13 a 1.

Further, in the embodiment mentioned above, the structure is realized byforming the shower head 13 a in the semicircular shape and providing theradial injection holes 13 a 1 therein, however, as shown in FIGS. 14 and15, the structure can be made by forming a radially expanded portion 13c expanding downward at the front end of the diffuser pipe 13, formingthe shower head 13 a by a mesh (a metal mesh), and forming the front endportion in a substantially semicircular shape. In this case, since awebbing of the mesh forms the injection holes 13 a 1, it is possible toeasily change and set a dispersing performance of the gas by changing anaspect (a magnitude and the number of the webbing) of the shower head 13a. Further, it is possible to inject and supply the gas with a wellbalance to a whole of the three-dimensional direction from the showerhead 13 a of the mesh formed in the substantially semispherical shape.In this case, at a time of forming the shower head 13 a by the mesh (themetal mesh), the structure can be realized by forming the radiallyexpanded portion 13 c expanding downward at the front end of thediffuser pipe 13 and covering by the shower head 13 a of the mesh in aplanner manner, as shown in FIG. 16.

Further, as shown in FIG. 17, the structure can be realized by formingthe shower head 13 a in a porous body capable of ventilating in asemispherical shape. In this case, since a large number of holes of theporous body form the injection holes 13 a 1, it is possible to easilychange and set the dispersing performance of the gas by changing a rawmaterial of the shower head 13 a. Further, it is possible to inject andsupply the gas with a well balance to a whole of the three-dimensionaldirection from the shower head 13 a of the semispherical porous body. Inthis case, at a time of forming the shower head 13 a by the porous rawmaterial, the structure can be realized by forming in a circular plateshape.

Further, in the embodiment mentioned above, the structure is realized byintegrally providing the shower head 13 a at the front end of thediffuser pipe 13, however, as shown in FIG. 19, the structure can berealized by integrally providing the shower head 13 a in the gasinjection port (provided on the circumferential surface of thecylindrical inflator) of the inflator 14. In this case, it is possibleto reduce the length of the gas flow passage from the inflator 14 to thegas passage 11 b of the air bag 11 so as to reduce the inflating anddeploying period of the air bag 11. In this case, in the embodimentshown in FIG. 19, the gas supply port 11 a of the air bag 11 isassembled in an outer periphery of a middle portion of the inflator 14in an air tight manner by using a fastening band 15.

Further, in the embodiment mentioned above, the structure is realized inthe air bag 11 having the gas supply port 11 a in the middle upperportion of the air bag 11, however, as shown in FIG. 20, it is a matterof course that the embodiment can be realized in an air bag having thegas supply port 11 a at the rear end portion of the air bag 11, and theembodiment can be realized in an air bag (not shown) having the gassupply port at the front end portion of the air bag.

In the embodiment shown in FIG. 20, the shower head 13 a provided at thefront end of the linear diffuser pipe 13 is coaxially arranged withrespect to the longitudinal direction of the gas passage 11 bcommunicating with the inflating chambers (the respective inflatingchambers in the front seat inflating portion and the rear seat inflatingportion) in the air bag 11. Further, in the embodiment shown in FIG. 20,since the shower head 13 a is arranged in the gas passage 11 b at theportion communicating with an inflating chamber 11 d 5 at the rear endof the air bag 11, it is possible to directly supply a part of the gasdispersed in the three-dimensional direction by the shower head 13 a tothe inflating chamber 11 d 5 of the air bag 11, whereby it is possibleto increase a gas dispersing effect (a bag damage reducing effect) andit is possible to reduce the inflating and deploying period of the rearseat inflating portion 11 d.

In the embodiment shown in FIG. 20, the shower head 13 a is provided atthe front end of the linear diffuser pipe 13, however, as shown in FIG.21, the structure can be realized by omitting the diffuser pipe 13 andintegrally providing the shower head 13 a in the gas injection portprovided in the front end portion of the cylindrical inflator 14. Inthis case, by omitting the diffuser pipe 13, it is possible to reducethe length of the gas flow passage from the inflator 14 to the gaspassage 11 b of the air bag 11, whereby it is possible to reduce theinflating and deploying period of the air bag 11. Further, by omittingthe diffuser pipe 13, it is possible to make the air bag module compactand reduce the cost.

Further, in the embodiment mentioned above, by employing the structureformed in the substantially J shape as the diffuser pipe 13, whereby asshown in FIG. 9, the inflator 14 is assembled in the roof side rail 21,the front end of the diffuser pipe 13 becomes substantially parallel tothe door glass surface 41, however, as shown in FIG. 22, the structurecan be also realized by curving the middle portion of the diffuser pipe13 to an external side of the vehicle body (a right side in FIG. 22) ata predetermined amount and forming so that the front end of the diffuserpipe 13 becomes substantially in parallel to the door glass surface 41.

Further, in the embodiment mentioned above, as shown in FIG. 1, thestructure is realized by forming so that the front end of the diffuserpipe 13 is arranged at a position a little to the rear of the B pillar23, however, the arrangement of the diffuser pipe 13 can be suitablychanged, and the structure can be realized by arranging so that thefront end of the diffuser pipe 13 overlaps with the B pillar 23. Alayout in such a case is as exemplified in FIG. 23, and in this layout,an inclined surface of a projection 33 a provided in the B pillargarnish 33 is arranged so as to oppose to the front end portion of thediffuser pipe 13.

Further, in the embodiment mentioned above, at a time of providing aplurality of injection holes 13 a 1 in the shower head 13 a, thestructure is realized by providing one hole in the center of the frontend and eight holes in the circumferential direction in one line, forexample, as shown in FIG. 8, however, the structure can be realized byforming the shower head 13 a, for example, in a closed-end cylindricalshape (can be realized by forming in the other polygonal tubular shapethan the cylindrical shape) and providing a plurality of injection holes13 a 1 in a bottom wall thereof (which may be flat or spherical) in amanner shown in FIG. 24 or 25. In this case, the respective injectionholes 13 a 1 in FIGS. 24 and 25 have the same diameter.

In the embodiment shown in FIG. 24, a plurality of injection holes 13 a1 are concentrically provided with respect to the center of the frontend of the shower head 13 a in a two-line arrangement so that therespective lines include eight holes, and one hole is provided in thecenter of the front end of the shower head 13 a. The arrangement in twolines in FIG. 24 may be replaced by an arrangement having three lines ormore, and the number of the holes in each of the lines is not limited toeight and can be suitably increased and reduced. Accordingly, in theembodiment mentioned above, it is possible to suitably set the gasdispersing effect on the basis of the arrangement of the injection holes13 a 1 and it is possible to reduce the bag damage and improve the gassupplying efficiency with a good balance.

On the contrary, in the embodiment shown in FIG. 25, inner and outerinjection holes 13 a 1 concentrically arranged in two lines and beingadjacent to each other in a radial direction are arranged in a zigzagmanner in a circumferential direction (alternately arranged along innerand outer circumferences in the circumferential direction so as not tocoincide radially as shown in FIG. 24). Accordingly, in the embodimentmentioned above, it is possible to prevent an interference at a timewhen the gas is injected from the inner and outer injection holes 13 a 1concentrically arranged in two lines and being adjacent to each other inthe radial direction, and it is possible to disperse the gas with a goodbalance from the respective injection holes 13 a 1 of the shower head 13a to the gas passage 11 b of the air bag 11, whereby it is possible tofurther reduce the bag damage and improve the gas supplying efficiency.

Further, in the embodiment mentioned above, as shown in FIGS. 6 to 8,the structure is realized by forming the shower head 13 a in thesemispherical shape, however, as shown in FIGS. 26 and 27, or as shownin FIGS. 28 and 29, the structure can be realized by forming the showerhead 13 a in a closed-end stepped cylindrical shape (the other polygonaltubular shapes than the cylindrical shape may be employed) havingmultiple stages becoming smaller toward the front end, or as shown inFIG. 30 by forming the front end of the shower head 13 a in anasymmetrical shape with respect to the center axis thereof, andproviding a plurality of injection holes 13 a 1 (13 a 1 and 13 a 3 inFIGS. 28 and 29) on a bottom wall thereof.

In the embodiment shown in FIGS. 26 and 27, the injection hole 13 a 1 isformed in the center of the front end on a bottom wall (a stepped bottomwall having two stages) of the shower head 13 a in an axial direction,and a plurality of injection holes 13 a 1 (having the same diameter asthat of the injection hole 13 a 1 in the center of the front end) areformed in the respective step portions formed on the bottom wall in aninclined manner. In the embodiment mentioned above, since the showerhead 13 a is formed in the stepped shape having the multiple stageshaving the diameter reduced toward the front end, it is possible tosecure the gas pressure within the front end of the shower head 13 a, itis possible to level the gas pressure at a time when the gas flows intothe respective injection holes 13 a 1, and it is possible to level thegas flow flowing through the respective injection holes 13 a 1. Further,by forming a plurality of injection holes 13 a 1 in the respective stepportions in the inclined manner, it is possible to concentrically form asubstantially conical gas flow expanding downward in a multiple manner,and it is possible to diffuse the gas flow with a good balance. Further,in the outlet of each of the injection holes 13 a 1, the gas flow isrectified due to a restriction of diffusion (dispersion) performed bythe stepped wall surface having an L-shaped cross section, and flows ina desired direction at a desired angle of diffusion.

On the contrary, in the embodiment shown in FIGS. 28 and 29, theinjection hole 13 a 1 having a complete round shape is formed in thecenter of the front end of the wide wall in the shower head 13 a in anaxial direction, and a plurality of injection holes 13 a 3 having a fanshape expanded in an axial direction and a circumferential directiontoward the front end (a fan shape expanded in any one direction may beemployed) are formed in the respective step portion formed on the bottomwall in an inclined manner. In the embodiment mentioned above, apressure loss due to a shearing resistance (a wall surface resistance)is increased in comparison with the injection hole having the completeround shape (the injection hole 13 a 1 in accordance with the embodimentshown in FIGS. 26 and 27) in the fan-shaped injection holes 13 a 3, andthe angle of diffusion of the gas flow is enlarged. Accordingly, bysuitably setting the angle of opening of the fan shape, it is possibleto adjust the gas flow so as to adjust the deploying property and thedirectivity of the air bag 11.

Further, in the embodiment shown in FIG. 30, the injection hole 13 a 1is formed in the axial direction in the center of the front end on thebottom wall of the shower head 13 a, and a plurality of injection holes13 a 1 (having the same diameter as that of the injection hole 13 a 1 inthe center of the front end) are respectively formed on an asymmetricalsurface thereof in an inclined manner. In the embodiment mentionedabove, by suitably setting an asymmetrical front end shape of the showerhead 13 a, it is possible to adjust the gas flow so as to adjust thedeploying property and the directivity of the air bag 11.

The respective injection holes 13 a 1 mentioned above (the injectionholes having the complete round shape) can be realized by forming in thestepped shape in which a back portion has a large diameter and reducinga thickness To of a minimum hole portion Ho, as exemplified in FIG. 31.In accordance with the embodiment mentioned above, it is possible toreduce the pressure loss in the injection holes 13 a 1 while securingthe strength required for the shower head 13 a. Further, by changing thethickness To of the minimum hole portion Ho (a length of the minimumhole), it is possible to adjust the amount of the pressure loss.

Further, the respective injection holes 13 a 1 mentioned above (theinjection holes having the complete round shape) can be realized byinclining with respect to the wall surface of the front end wall at atime of being formed on the front end wall (the bottom wall) of theshower head 13 a, as exemplified in FIG. 32. In the embodiment mentionedabove, an apparent opening area So of the inclined injection hole 13 a 1is reduced and the amount of pressure loss is increased. Further, it ispossible to adjust the gas flow by changing the distribution and theangle of incline of the inclined injection holes 13 a 1, and it is alsopossible to adjust the deploying property and the directivity of the airbag 11.

Further, the structure can be realized by forming the shower head 13 ain a closed rectangular tubular shape (the other closed-end polygonaltubular shapes or closed-end cylindrical shapes may be employed) asexemplified in FIG. 33, forming the injection hole 13 a 1 having thecomplete round shape in the center of the front end wall in the showerhead 13 a and forming four injection holes 13 a 4 having a substantiallytriangular shape so as to ride over the front end wall of the showerhead 13 a and the circumferential wall. In accordance with theembodiment mentioned above, it is possible to disperse (diffuse) the gasin multiple directions on the basis of a simple shape (structure).Further, the injection holes 13 a 4 having the substantially triangularshape riding over the front end wall and the circumferential wall in theshower head 13 a can be easily formed by obliquely cutting the front endof the shower head 13 a, whereby it is possible to easily manufacturethe shower head 13 a and it is possible to reduce the cost of the showerhead 13 a.

Further, in the embodiment mentioned above, as shown in FIGS. 6 to 8,the structure is realized by forming so that the inner diameter and theouter diameter of the upper end portion in the shower head 13 a becomesubstantially equal to the inner diameter and the outer diameter of thelower end portion in the diffuser pipe 13, and connecting them inaccordance with a welding or the like. However, as shown in FIGS. 34 and35, the structure can be realized by forming so that the inner diameterand the outer diameter of the lower end portion (the front end portion)in the diffuser pipe 13 become smaller than the inner diameter and theouter diameter of the upper end portion in the shower head 13 a, andfitting and fixing the shower head 13 a to an outer circumference of thelower end portion in the diffuser pipe 13 for example, in accordancewith a spring fastening (or a caulking, a welding or the like). Inaccordance with the embodiment mentioned above, by replacing the showerhead 13 a, it is possible to easily change the gas dispersing property,for example, corresponding to the shape, the magnitude or the like ofthe air bag 11. Further, since the shower head 13 a can be manufacturedindependently, it is easy to work the injection hole 13 a 1 with respectto the shower head 13 a and it is possible to widely reduce the costsince the common use of the diffuser pipe 13 is possible.

Further, in the embodiment structured such that in a state that thediffuser pipe 13 and the shower head 13 a shown in FIGS. 34 and 35 areemployed, the gas supply port 11 a forming portion of the air bag 11 isfixed to the step portion formed by the front end portion of thediffuser pipe 13 and the shower head 13 a by using a fastening band 15as shown in FIG. 35, it is possible to fixe the diffuser pipe 13 and theshower head 13 a to the air bag 11 by effectively utilizing the stepportion formed by the diffuser pipe 13 and the shower head 13 a, wherebyit is possible to improve an assembling operability and a fixingstrength.

Further, in the embodiment mentioned above, the structure is realized byproviding in a symmetrical with respect to the longitudinal direction(the lateral direction in the drawing), for example, as shown in FIG. 8,at a time of providing with a plurality of injection holes 13 a 1 in theshower head 13 a, however, as shown in FIG. 36, 37 or 38, the structurecan be realized by providing with a plurality of injection holes 13 a 1in an asymmetrical with respect to the longitudinal direction (thelateral direction in the drawing).

In the embodiment shown in FIG. 36, a hole diameter (having the samediameter as that of the injection hole 13 a 1 in the center of the frontend) of three front seat injection holes 13 a 1 (Fr) provided in a leftside of the drawing is made larger than a hole diameter of three rearseat injection holes 13 a 1 (Rr) provided in a right side of thedrawing, and the opening areas of the respective three front seatinjection holes 13 a 1 (Fr) and rear seat injection holes 13 a 1 (Rr)(an opening area Sf of the front seat injection holes and an openingarea Sr of the rear seat injection holes) are set corresponding to thecapacities of the inflating chambers of the front seat inflating portion11 c and the rear seat inflating portion 11 d in the air bag 11.

In the embodiment mentioned above, it is possible to substantiallycoincide the inflating and deploying timing of the front seat inflatingportion 11 c with that of the rear seat inflating portion 11 d in theair bag 11 without increasing man hour for working the respectiveinjection holes 13 a 1, 13 a 1(Fr) and 13 a 1(Rr) in the shower head 13a, so as to reduce the time from starting inflation and deployment ofthe air bag 11 until completion at a low cost, and it is possible toimprove the motion during inflating and deploying the air bag 11.

On the contrary, in the embodiment shown in FIG. 37, the hole diameter(larger than the hole diameter of the injection hole 13 a 1 in thecenter of the front end) of three front seat injection holes 13 a 1(Fr)provided in the left side in the drawing is gradually reduced toward thecenter of the front end in the shower head 13 a (in particular, one at aleft end has a large diameter and two rightward thereof have middlediameters). In the embodiment mentioned above, it is possible togradually reduce the injected gas flow corresponding to the holediameter of the injection hole 13 a 1(Fr) in the left side in thedrawing, it is possible to permit the gas to have a directivity, and itis possible to adjust the motion during inflating and deploying the airbag 11. In this case, in the embodiment shown in FIG. 37, the holediameter of three rear seat injection holes 13 a 1(Rr) provided in theright side in the drawing is set to be equal to the hole diameter of theinjection hole 13 a 1 in the center of the front end.

Further, in the embodiment shown in FIG. 38, the number (five) of thefront seat injection holes 13 a 1(Fr) provided in the left side in thedrawing is set to be larger than the number (three) of the front seatinjection holes 13 a 1(Fr) provided in the right side in the drawing,and the opening areas of the front seat injection holes 13 a 1(Fr) andthe rear seat injection holes 13 a 1(Rr) (the opening area Sf of thefront seat injection holes and the opening area Sr of the rear seatinjection holes) are set corresponding to the capacities of theinflating chambers of the front seat inflating portion 11 c and the rearseat inflating portion 11 d in the air bag 11 (set to Sf>Sr). Further,the hole diameter of the respective front seat injection holes 13 a1(Fr) and the hole diameter of the respective front seat injection holes13 a 1(Fr) are set to be equal to the hole diameter of the injectionhole 13 a 1 in the center of the front end.

In the embodiment mentioned above, it is possible to substantiallycoincide the inflating and deploying timing of the front seat inflatingportion 11 c with that of the rear seat inflating portion 11 d in theair bag 11 by working (working so as to increase the number of theinjection holes in a side of increasing the opening area) the respectiveinjection holes 13 a 1, 13 a 1(Fr) and 13 a 1(Rr) in the shower head 13a by the same tool, it is possible to reduce the period of time fromstarting inflation and deployment of the air bag 11 until completion,while reducing the bag damage due to an increase of the number of theinjection holes (a reduction of the gas flow speed), and it is alsopossible to improve the motion during inflating and deploying the airbag 11.

Further, in the embodiment mentioned above, as shown in FIGS. 1 and 2,the structure is realized by forming so that the inflating chamber isnot provided below the front end of the shower head 13 a (immediatelybelow the gas supply port 11 a) in the air bag 11, however, as shown inFIG. 39, 40 or 41, the structure can be realized by forming so that anauxiliary inflating chamber 11 h is provided immediately below the gassupply port 11 a (below the front end of the shower head) in the air bag11. In this case, in the air bag 11 shown in FIG. 39, 40 or 41, therespective inflating chambers (cells) of the front seat inflatingportion 11 c and the rear seat inflating portion 11 d are communicatedwith the gas passage 11 b only at the upper end.

In the embodiment shown in FIG. 39, the auxiliary inflating chamber 11 hof the air bag 11 is communicated with the gas passage 11 b at the upperend immediately below the gas supply port 11 a (below the front end ofthe shower head) so as to be extended in the vertical direction). In theembodiment mentioned above, the gas flows to the auxiliary inflatingchamber 11 h of the air bag 11 during inflating and deploying the airbag 11, thereby promoting the air bag 11 to deploy downward.Accordingly, it is possible to reduce the period of time untilcompleting the deployment of the air bag 11.

On the contrary, in the embodiment shown in FIG. 40, as well as the gassupply port 11 a of the air bag 11 is provided so as to be displacedforward in comparison with FIG. 39, the auxiliary inflating chamber 11 his provided close to the front seat inflating portion 11 c. Further, theauxiliary inflating chamber 11 h communicates the lower end thereof withthe lower end of the rear seat inflating portion 11 d. In accordancewith the embodiment mentioned above, as well as it is possible toquickly supply the gas from the gas supply port 11 a of the air bag 11to the front seat inflating portion 11 c, it is possible to supply thegas to the lower end of the rear seat inflating portion 11 d through theauxiliary inflating chamber 11 h, whereby it is possible to furtherreduce the period of time until completing the deployment of the air bag11. Here, in the case that the gas supply port 11 a of the air bag 11 isprovided so as to be displaced rearward in comparison with FIG. 39, itis desirable that the auxiliary inflating chamber 11 h is provided closeto the rear seat inflating portion 11 d, and the lower end thereof iscommunicated with the lower end of the front seat inflating portion 11c.

Further, in the embodiment shown in FIG. 41, the gas supply port 11 a ofthe air bag 11 is provided so as to be displaced forward in comparisonwith FIG. 39, and the auxiliary inflating chamber 11 h is provided closeto the front seat inflating portion 11 c. Further, the auxiliaryinflating chamber 11 h communicates the lower end thereof with therespective lower ends of the front seat inflating portion 11 c and therear seat inflating portion 11 d. In the embodiment mentioned above, aswell as it is possible to quickly supply the gas from the gas supplyport 11 a of the air bag 11 to the front seat inflating portion 11 c, itis also possible to supply the gas to the respective lower ends of thefront seat inflating portion 11 c and the rear seat inflating portion 11d through the auxiliary inflating chamber 11 h, whereby it is possibleto further reduce the period of time until completing the deployment ofthe air bag 11.

Further, in the embodiment shown in FIG. 39, 40 or 41, in the case ofsetting the opening area of the passage communicating the auxiliaryinflating chamber 11 h with the front seat inflating portion 11 c (theopening area in the front portion of the upper gas passage 11 b in theembodiment shown in FIGS. 39 and 40, and a sum of the opening area inthe front portion of the upper gas passage 11 b and the opening area ofthe lower gas passage 111 in the embodiment shown in FIG. 41), and theopening area of the passage communicating the auxiliary inflatingchamber 11 h with the rear seat inflating portion 11 d (the opening areain the rear portion of the upper gas passage 11 b in the embodimentshown in FIG. 39, and a sum of the opening area in the rear portion ofthe upper gas passage 11 b and the opening area in the rear portion ofthe lower gas passage 111 in the embodiment shown in FIGS. 40 and 41)according to the capacities of the inflating chambers in the front seatinflating portion 11 c and the rear seat inflating portion 11 d, it ispossible to substantially coincide the inflating and deploying timing ofthe front seat inflating portion 11 c with that of the rear seatinflating portion 11 d in the air bag 11 while reducing the period oftime until completing the deployment of the air bag 11.

Further, at a time of realizing the present invention, as shown in FIG.42, it is possible to differentiate the distribution in the longitudinaldirection of the front seat injection holes 13 a 1(Fr) and the rear seatinjection holes 13 a 1(Rr) provided in the shower head 13 a with respectto the center of the front end (in which the injection hole 13 a 1 isprovided) in the shower head. In the embodiment mentioned above, it ispossible to adjust the injection pressures of the gas passing throughthe front seat injection holes 13 a 1(Fr) and the rear seat injectionholes 13 a 1(Rr) (in FIG. 42, it is possible to strengthen the forwardgas injection pressure), and it is possible to adjust the inflating anddeploying timing of the front seat inflating portion 11 c and the rearseat inflating portion 11 d in the air bag 11. In this case, the holediameters of the respective injection holes 13 a 1, 13 a 1(Fr) and 13 a1(Rr) are the same.

Further, as shown in FIG. 43, it is possible to form the rectangularinjection hole 13 a 5 provided in the shower head 13 a in a long holebeing long in the longitudinal direction, or as shown in FIG. 44, it ispossible to make the opening area (the hole diameter) of the injectionholes 13 a 1(Fr) and 13 a 1(Rr) (the injection holes in the right andleft ends in FIG. 44) most apart in the longitudinal direction from thecenter of the front end of the shower head among the injection holes 13a 1 provided in the shower head 13 a larger than the opening area (thehole diameter) of the other injection holes. In accordance with theembodiments, it is possible to strengthen the gas flow in thelongitudinal direction, it is possible to positively inflate and deploythe air bag 11 on the basis of the same gas flow, and it is possible toinflate and deploy the air bag 11 with applying the directivity in thelongitudinal direction.

Further, as shown in FIG. 45, it is possible to differentiate theopening area (the hole diameter) of the injection holes 13 a 1 providedin the shower head 13 a between the inner side and the outer side in thevehicle width direction (in FIG. 45, the opening area in the inner sidein the vehicle width direction is made larger), or as shown in FIG. 46,it is possible to differentiate the number of the injection holes 13 a 1having the same diameter provided in the shower head 13 a between theinner side and the outer side in the vehicle width direction (in FIG.46, the number in the inner side in the vehicle width direction is madelarger).

In the embodiments mentioned above, it is possible to inflate and deploythe air bag 11 in the portion in which the shower head 13 a is arrangedtoward the inner side or the outer side in the vehicle width direction.Accordingly, for example, in the case of setting so as to inflate anddeploy the air bag toward the inner side in the vehicle width direction,it is possible to prevent the air bag 11 in the middle of inflation anddeployment from being caught on the upper end portion of the B pillargarnish 33 or the like, and further, in the case of setting so as toinflate and deploy the air bag 11 toward the outer side in the vehiclewidth direction, it is possible to inflate and deploy the air bag 11along the door glass (the side glass) surface 41.

Further, as shown in FIG. 47, it is possible to form the gas supply port11 a of the air bag 11 to which the shower head 13 a is inserted in ashape expanding at a predetermined angle θo toward the gas passage 11 b,and it is possible to make an angle of diffusion (θf+θr) in thelongitudinal direction of the gas supplied from the shower head 13 aequal to or less than the predetermined angle θo. In accordance with theembodiment mentioned above, even when the shower head 13 a is arrangedat any position of the gas supply port 11 a in the air bag 11, the gasinjected from the shower head 13 a is not directly brought into contactwith the gas supply port forming portion in the air bag 11, whereby itis possible to both reduce the damage on the gas supply port 11 aforming portion in the air bag 11 and improve a diffusing property.

Further, as shown in FIG. 48, in addition that the auxiliary inflatingchamber 11 h communicated with the gas passage 11 b at the upper endbelow the front end of the shower head 13 a and extending in thevertical direction is provided in the air bag, it is possible to set theangle of diffusion (θf+θr) in the longitudinal direction of the gassupplied from the shower head 13 a to be equal to or greater than thepredetermined value, so that the gas is injected to the forward portionrather than the R end point Pf in front of the upper end of theauxiliary inflating chamber 11 h and to the rearward portion rather thanthe R end point Pr at the back of the upper end. In accordance with theembodiment mentioned above, in addition to securing the inflow of thegas to the auxiliary inflating chamber 11 h, it is possible todistribute the gas well to the forward portion and the rearward portionof the gas passage 11 b, and it is possible to improve the gasdistributing property to the forward portion, the rearward portion andthe lower portion from the shower head 13 a.

Further, as shown in FIG. 48, in the case that the angle of diffusion θfthe gas diffusing from the shower head 13 a to the forward portion ismade different from the angle of diffusion θr to the rearward portion(in FIG. 48, θf>θr is set according to a ratio of capacity of theinflating chamber between the front seat inflating portion 11 c and therear seat inflating portion 11 d), it is possible to change the gasdistribution to the forward portion and the rearward portion in the gaspassage 11 b according to the shape of the air bag 11 (for example, aratio of capacity of the inflating chamber or a shape of the inflatingchamber between the front seat inflating portion 11 c and the rear seatinflating portion 11 d), and it is possible to inflate and deploy theair bag 11 in an optimum state.

Further, in the embodiment mentioned above, in order to disperse the gassupplied from the inflator 14 in the three-dimensional direction so asto supply to the gas passage 11 b in the air bag 11, the structure isrealized by providing with the dispersing means (the shower head 13 a)in the gas supply side, however, as shown in FIG. 49, the structure canbe realized by providing with a dispersing means (a triangular bag basefabric 11 j) in the air bag side. The triangular bag base fabric 11 j(in which a seal agent is previously applied onto both front and backsurfaces) is formed by being gripped between two base fabrics and beingsewed along a triangular peripheral edge at a time when the sewn air bag11 is produced by two base fabrics (in which a seal agent is previouslyapplied to a mating face), in which a top portion exists immediatelybelow the opening of the diffuser pipe 13 so as to disperse the gassupplied from the inflator through the diffuser pipe 13 in thethree-dimensional direction and supply to the gas passage 11 b in theair bag 11.

Further, in accordance with the embodiment mentioned above, the presentinvention is applied to the head portion protecting air bag apparatusfor the passenger car vehicle. However, it is a matter of course thatthe present invention can be applied to a head portion protecting airbag apparatus for vehicles other than the passenger car, and the presentinvention can be applied to the other various air bag apparatusesstructured such that the air bag housed in a part of the vehicle in afold-up manner inflates and deploys due to the gas supplied from theinflator so as to protect the occupant, for example, an air bagapparatus for an assistant driver's seat which is assembled in aninstrument panel, air bag apparatuses which are assembled in respectiveportion of the seats, and the like, on the basis of a suitablemodification.

1. An air bag apparatus comprising: an air bag that is housed along aroof side rail and is inflated and deployed in a curtain-like shapealong a vehicle compartment side wall due to gas supplied from aninflator that is disposed outside the air bag and is arranged in acenter portion along a longitudinal direction of a vehicle so as toprotect a head portion of an occupant, the air bag being provided withan inflating portion for a front seat and an inflating portion for arear seat; a gas passage for communicating upper portions of both of theinflating portions; a single gas supply port that opens into the gaspassage from above; and a shower head for dispersing the gas suppliedfrom the inflator in a plurality of directions and being disposed so asto face the gas supply port of the air bag, the shower head having aplurality of injection holes which are directed in the plurality ofdirections.
 2. An air bag apparatus according to claim 1, wherein theshower head is formed in a semispherical shape and has the plurality ofinjection holes on a spherical surface thereof.
 3. An air bag apparatusaccording to claim 1, wherein the injection holes of the shower head areprovided symmetrically with respect to a point of a center of the showerhead.
 4. An air bag apparatus comprising: an air bag that is housedalong a roof side rail and is inflated and deployed in a curtain-likeshape along a vehicle compartment side wall due to gas supplied from aninflator so as to protect a head portion of an occupant, the air bagbeing provided with an inflating portion for a front seat and aninflating portion for a rear seat and a gas passage for communicatingupper portions of both of the inflating portions; and a shower head fordispersing the gas supplied from the inflator in a forward, rearward anddownward directions and being disposed so as to face the gas passage ofthe air bag, the shower head having a plurality of injection holes whichare directed in the forward, rearward and downward directions, theforward direction being opposite to the rearward direction and thedownward direction being perpendicular to the forward and rearwarddirections, wherein opening areas of an injection hole for the frontseat and an injection hole for the rear seat provided in the shower headare set according to capacities of expansion chambers in the front seatinflating portion and the rear seat inflating portion.
 5. An air bagapparatus according to claim 1, wherein the shower head is formed by amesh.
 6. An air bag apparatus according to claim 5, wherein the showerhead is formed in a semispherical shape.
 7. An air bag apparatusaccording to claim 1, wherein the shower head is formed by a porousbody.
 8. An air bag apparatus according to claim 7, wherein the showerhead is formed in a semispherical shape.
 9. An air bag apparatusaccording to claim 1, wherein the shower head is provided in a front endof a diffuser pipe assembled in the inflator.
 10. An air bag apparatusaccording to claim 1, wherein the shower head is integrally provided inthe inflator.
 11. An air bag apparatus according to claim 1, wherein theshower head does not protrude within the gas passage of the air bag. 12.An air bag apparatus according to claim 11, wherein the inflator isarranged in a center portion in a longitudinal direction of a vehicle.13. An air bag apparatus according to claim 12, wherein the inflator isarranged in a longitudinal direction along the roof side rail above theair bag.
 14. An air bag apparatus according to claim 13, wherein theinflator is arranged in a vehicle width direction along a roof panelabove the air bag.
 15. An air bag apparatus according to claim 13,wherein the diffuser pipe is formed in a substantially J shape.
 16. Anair bag apparatus according to claim 1, wherein the shower head iscoaxially arranged with respect to the longitudinal direction of the gaspassage communicating with the inflating chamber of the air bag.
 17. Anair bag apparatus according to claim 16, wherein the inflator isarranged in front of or at the rear of the vehicle of the air bag. 18.An air bag apparatus according to claim 17, wherein the shower head isarranged in the gas passage at a portion of the air bag communicatingwith the inflating chamber.
 19. An air bag apparatus according to claim1, wherein the plurality of injection holes provided in the shower headare concentrically arranged with a center of the front end of the showerhead so as to form a plurality of lines.
 20. An air bag apparatusaccording to claim 19, wherein a plurality of inner and outer injectionholes concentrically arranged and being adjacent to each other in aradial direction are arranged in a circumferential direction so as toform a zigzag form.
 21. An air bag apparatus according to claim 19,wherein the shower head is formed in a stepped shape having multiplesteps which become smaller toward the front end, and the plurality ofinjection holes is formed in the respective step portions in an inclinedmanner.
 22. An air bag apparatus according to claim 19, wherein theinjection holes are formed in a fan shape expanding toward the frontend.
 23. An air bag apparatus according to claim 1, wherein the frontend of the shower head is formed in an asymmetrical shape with respectto a center axis thereof and the injection holes are formed in theasymmetrical surface.
 24. An air bag apparatus according to claim 1,wherein the injection holes are formed in a stepped shape and athickness of a minimum hole portion is made small.
 25. An air bagapparatus according to claim 1, wherein the injection holes formed inthe front end wall of the shower head are inclined with respect to thewall surface of the front end wall.
 26. An air bag apparatus accordingto claim 1, wherein the shower head is formed in a closed-endcylindrical shape or a closed-end polygonal tubular shape, the injectionholes are formed in the front end wall of the shower head, and theinjection holes are formed so as to ride over the front wall of theshower head and a peripheral wall.
 27. An air bag apparatus according toclaim 9, wherein the front end portion of the diffuser pipe is formed soas to have a small diameter and the shower head is fitted and fixed toan outer periphery of the front end portion of the diffuser pipe.
 28. Anair bag apparatus according to claim 27, wherein a gas supply portforming portion of the air bag is fixed to the step portion formed bythe front end portion of the diffuser pipe and the shower head.
 29. Anair bag apparatus according to claim 4, wherein hole diameters are madedifferent between the front seat injection hole and the rear seatinjection hole which are provided in the shower head, whereby it ispossible to set the opening areas of the front seat injection hole andthe rear seat injection hole according to the capacities of theinflating chambers in the front seat inflating portion and the rear seatinflating portion.
 30. An air bag apparatus according to claim 29,wherein the front seat injection holes and the rear seat injection holesare respectively constituted by the plurality of injection holes, and ahole diameter of any one thereof is gradually reduced toward the centerof the front end in the shower head.
 31. An air bag apparatus accordingto claim 4, wherein numbers of holes are made different between thefront seat injection hole and the rear seat injection hole which areprovided in the shower head, whereby it is possible to set the openingareas of the front seat injection hole and the rear seat injection holeaccording to the capacities of the inflating chambers in the front seatinflating portion and the rear seat inflating portion.
 32. An air bagapparatus according to claim 4, wherein an auxiliary inflating chambercommunicating with the gas passage at an upper end below the front endof the shower head so as to extend in a vertical direction is providedin the air bag.
 33. An air bag apparatus according to claim 32, whereina lower end of the auxiliary inflating chamber is communicated with atleast one of the front seat inflating portion and the rear seatinflating portion.
 34. An air bag apparatus according to claim 32,wherein an opening area of a passage for communicating the auxiliaryinflating chamber with the front seat inflating portion and an openingarea of a passage for communicating the auxiliary inflating chamber withthe rear seat inflating portion are set according to the capacities ofthe inflating chambers in the front seat inflating portion and the rearseat inflating portion.
 35. An air bag apparatus according to claim 1,wherein distribution in a longitudinal direction with respect to thecenter of the front end in the shower head is made different between thefront seat injection hole and the rear seat injection hole which areprovided in the shower head.
 36. An air bag apparatus according to claim1, wherein the injection holes provided in the shower head are formed ina long hole longer in the longitudinal direction.
 37. An air bagapparatus according to claim 1, wherein an opening area of the injectionhole being most apart in the longitudinal direction from the center ofthe front end of the shower head among the plurality of injection holesprovided in the shower head is made larger than an opening area of theother injection holes.
 38. An air bag apparatus according to claim 1,wherein opening areas of the injection holes provided in the shower headare made different between an inner portion and an outer portion in thevehicle width direction.
 39. An air bag apparatus according to claim 1,wherein numbers of the injection holes provided in the shower head aremade different between an inner portion and an outer portion in thevehicle width direction.
 40. An air bag apparatus according to claim 1,wherein the gas supply port of the air bag to which the shower head isinserted is formed in a shape expanding at a predetermined angle towardthe gas passage, and an angle of diffusion of the gas supplied from theshower head is made equal to or less than the predetermined angle. 41.An air bag apparatus according to claim 1, wherein an auxiliaryinflating chamber communicating with the gas passage at an upper endbelow the front end of the shower head and extending in a verticaldirection is provided in the air bag, and an angle of diffusion in thelongitudinal direction of the gas supplied from the shower head is setto be equal to or greater than a predetermined value so that the gas isinjected farther forward than an end point disposed in a forward portionof the upper end of the auxiliary inflating chamber and farther rearwardthan an end point disposed in a rearward portion of the upper end. 42.An air bag apparatus according to claim 41, wherein the angle of forwarddiffusion of the gas from the shower head is made different from theangle of rearward diffusion.
 43. An air bag apparatus according to claim1, wherein: the plurality of directions are a forward direction, arearward direction and a downward direction, and the forward directionis opposite to the rearward direction and the downward direction isperpendicular to the forward and rearward directions.
 44. An air bagapparatus comprising: an air bag that is housed along a roof side railand is inflated and deployed in a curtain-like shape along a vehiclecompartment side wall due to gas supplied from an inflator that isdisposed outside the air bag and is arranged in a center portion along alongitudinal direction of the vehicle so as to protect a head portion ofan occupant, the air bag being provided with an inflating portion for afront seat and an inflating portion for a rear seat; a gas passage forcommunicating upper portions of both of the inflating portions; a singlegas supply port that opens into the gas passage from above; and a showerhead for dispersing the gas supplied from the inflator in at least threedirections and being disposed so as to face the gas supply port of theair bag, the shower head having a plurality of injection holes which aredirected in the three directions, the three directions including aforward direction toward a front of the vehicle, a rearward directiontoward a rear of the vehicle, and a downward direction.